With the development of technologies, there are more and more applications that control a device by detecting a natural action of a user, where applications that interact with the device by tracking an eye include the following applications.
The single lens reflex EOS 3 published by Canon has an exclusive eye control focusing function with 45 focusing points, which can automatically detect the motion of the pupil of the user eyeball that is watching the eyepiece of the camera. The eyeball is lighted by an infrared light emitting diode installed on the frame of the camera eyepiece, and the infrared light reflected back by the eyeball is cast onto an eye control BASIS (base stored image sensor). After the system detects the relative relationship between a position of the eyeball pupil and a calibration position, the camera identifies which focusing point in the focusing points is being watched by the user, so as to determine a sight line direction of the user, and perform automatic focusing on an object in the direction.
Tobii Technology develops an eye control interaction system, where an eye tracker (eye tracker) shoots and locates in real time a micro projection pattern reflected on the user eyeball (or directly shoots and locates the eyeball motion), so that the system can very precisely track a direction watched by the eye, to perform user eye control interaction or analyze a user reading behavior.
Google discloses, in U.S. Patent publication No. 2012/0290401, an apparatus and a method for determining a direction watched by an eye of a user through a wearable device, where the position of the user pupil is detected in real time by installing a camera or a CCD on a pair of glasses, so that the sight line direction of the user eye can be obtained.
As can be seen from the above, in the prior art, the sight line direction of the user is mainly obtained through the image on the eyeball surface. If the position of the focusing point of the eye is desired, the distance between the object and the eye is generally preset, as described in the foregoing eye control interaction technology, and the position of the focusing point can be obtained according to the sight line direction of the user and the set distance. In this case, if the distance between the object and the eye is not known, the position of the focusing point of the eye cannot be obtained. Alternatively, as disclosed in international patent publication No. WO2005077258A1, the position of the eye focusing point is obtained according to sight line directions of two eyes of the user and the intersection between the sight lines, so in this case, the sight line directions of the two eyes of the user need to be detected simultaneously, and the detection precision is not very high.
Medically, a fundus camera (Fundus Camera) is often used in ophthalmic diagnosis, where refined pictures of the fundus retina are captured to assist in diagnosis of some possible ophthalmic diseases, including determination of the eye diopter, as recorded in U.S. Pat. No. 7,001,020. However, the patent requires that the user stares at a specific target and has a test before an optical parameter of an eye can be determined. Therefore, the position of the focusing point of the eye in daily use cannot be determined.